ABSTRACT
Toxic heavy metals are often considered to be a group of metals and metalloids that have a relatively high density, occur in multiple oxidation states, and exert toxic effects on living organisms even upon exposure in low concentrations. Most of these heavy metals have widespread industrial applications. As a result of their industrial applications and irresponsible anthropogenic activities, the natural environment has been contaminated with these toxic metals. Therefore, scientists and engineers must pay utmost attention to remediate and mitigate the harmful effect of toxic metal pollution. In this context, biological remediation, specifically microbe-mediated remediation, could potentially be an effective solution to this problem since microbe-mediated remediation is a cost-effective, noninvasive, and efficient method to mitigate the harmful effects of toxic heavy metals. Microorganisms are the most ubiquitous, metabolically diverse, and abundant group of organisms in the world. They are capable of remediating heavy metals by a wide range of pathways that may include oxidation or reduction of heavy metals, immobilization of heavy metals in the environment, or entrapment of heavy metals within the microbial cell. Therefore, compared to conventional physico-chemical remediation, microbe- mediated metal remediation may be a more suitable strategy for the remediation of metals from the contaminated environment.
